{"id":578,"date":"2022-04-05T12:22:19","date_gmt":"2022-04-05T02:22:19","guid":{"rendered":"http:\/\/www.vk1zdj.net\/?p=578"},"modified":"2022-04-05T12:22:19","modified_gmt":"2022-04-05T02:22:19","slug":"a-5-8th-wave-antenna-for-146-mhz","status":"publish","type":"post","link":"https:\/\/www.vk1zdj.net\/?p=578","title":{"rendered":"A 5\/8th Wave Antenna for 146 Mhz."},"content":{"rendered":"\n<p>Last weekend I did some work for WICEN with the National Capital Rally, and during the drive in I remembered how terrible access to the 146.900 Mhz repeater on Isaacs Ridge was for me in the Xtrail.   Normally, the car simply has a stainless steel 1\/4 wave that gets into Mt Ginini Just fine, but from home I can never get into 146.9.<\/p>\n\n\n\n<p>While passing in times for my SOS checkpoint, I remembered that I used to own a 5\/8 wave antenna for VHF &#8211; It was especially handy for getting just a little extra gain for locations that were a little ropey.  I searched everywhere in the Garage, and I must have lent it out &#8211; Gone forever&#8230;.<\/p>\n\n\n\n<p>I have a handful of old CB antennas, so I decided to make one based on a little internet research.  My memory was correct &#8211; The antenna is literally made from about 11 turns of wire over about 40mm to match the radiator, and a single vertical wire.   The inductance on the base is to lower the angle of radiation while making the antenna look like a 3\/4 wave whip &#8211; thus providing gain over a standard 1\/4 wave whip.  The length of the radiator was about 1200mm for 146 Mhz.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><a href=\"http:\/\/www.vk1zdj.net\/wp-content\/uploads\/2022\/04\/Ant-close.png\"><img decoding=\"async\" loading=\"lazy\" width=\"271\" height=\"673\" src=\"http:\/\/www.vk1zdj.net\/wp-content\/uploads\/2022\/04\/Ant-close.png\" alt=\"\" class=\"wp-image-579\" srcset=\"https:\/\/www.vk1zdj.net\/wp-content\/uploads\/2022\/04\/Ant-close.png 271w, https:\/\/www.vk1zdj.net\/wp-content\/uploads\/2022\/04\/Ant-close-121x300.png 121w, https:\/\/www.vk1zdj.net\/wp-content\/uploads\/2022\/04\/Ant-close-80x199.png 80w\" sizes=\"(max-width: 271px) 100vw, 271px\" \/><\/a><\/figure>\n\n\n\n<p>A quick trim with a knife cut the black heat shrink sleeve off, leaving the wire element which I unwound to allow it to be reused.  I wound the necessary 11 turns at the bottom and secured the with a piece of clear tape.  I then ran the wire in basically a straight line for 1300mm and dropped a piece of black double wall glue based heat shrink on it and loaded it onto the car.<\/p>\n\n\n\n<p>My MFJ 259 quickly told me that the antenna was resonant at about 136Mhz, so I trimmed some length off and tried again.  I quickly arrived at resonance at 146Mhz, and a SWR of 1.3:1, so I tried the non-accessible Isaacs Ridge repeater.   Ker-Chunk!!!   A S1, slightly noisy response, but a response nonetheless.    I trimmed the excess biberglass of the stick, and shrunk the heat shrink down.<\/p>\n\n\n\n<p>And now I own a 5\/8 wave for VHF &#8211; Nice and robust!<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Last weekend I did some work for WICEN with the National Capital Rally, and during the drive in I remembered how terrible access to the 146.900 Mhz repeater on Isaacs Ridge was for me in the Xtrail. Normally,&#8230; <\/p>\n","protected":false},"author":1,"featured_media":580,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false},"categories":[6,9],"tags":[],"jetpack_featured_media_url":"https:\/\/www.vk1zdj.net\/wp-content\/uploads\/2022\/04\/Antenna.png","_links":{"self":[{"href":"https:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/posts\/578"}],"collection":[{"href":"https:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vk1zdj.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=578"}],"version-history":[{"count":2,"href":"https:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/posts\/578\/revisions"}],"predecessor-version":[{"id":582,"href":"https:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/posts\/578\/revisions\/582"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/media\/580"}],"wp:attachment":[{"href":"https:\/\/www.vk1zdj.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=578"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vk1zdj.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=578"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vk1zdj.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=578"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}